Lymphocytosis is a medical condition where there is an increased number of lymphocytes in the blood. Lymphocytes are a type of white blood cells that play a crucial role in the immune system.

Having an increased number of lymphocytes can be a sign of an underlying medical condition. In this article, we will discuss the 7 common causes of lymphocytosis.

1. Infections

Infections are a common cause of lymphocytosis. When the body is fighting off an infection, the lymphocytes respond by producing antibodies. This results in an increase in the number of lymphocytes in the blood.

Some examples of infections that can cause lymphocytosis include:.

HIV/AIDS
Hepatitis
Tuberculosis
Infectious mononucleosis (commonly known as mono)

2. Autoimmune Diseases

Autoimmune diseases are conditions where the immune system attacks the body’s own cells and tissues. This can result in an increased number of lymphocytes in the blood. Some examples of autoimmune diseases that can cause lymphocytosis include:.

Lupus
Rheumatoid arthritis
Multiple sclerosis
Celiac disease

3. Medications

There are certain medications that can cause lymphocytosis as a side effect. These medications include:.

Corticosteroids
Antiepileptic drugs
Antidepressants
Chemotherapy drugs

4. Cancer

Cancer is a common cause of lymphocytosis. In some cases, cancer cells can stimulate the lymphocytes to reproduce rapidly, resulting in an increased number of lymphocytes in the blood. Some examples of cancers that can cause lymphocytosis include:.

Leukemia
Lymphoma
Multiple myeloma

5. Stress

Stress can also cause lymphocytosis. When we experience stress, our bodies respond by releasing cortisol. Cortisol is a hormone that can stimulate the production of lymphocytes, resulting in an increased number of lymphocytes in the blood.

6. Hypersensitivity Reactions

Hypersensitivity reactions occur when the immune system overreacts to a substance that is normally harmless. This can cause an increased number of lymphocytes in the blood. Some examples of hypersensitivity reactions that can cause lymphocytosis include:.

Allergies
Asthma
Eczema

7. Immunodeficiency Disorders

Immunodeficiency disorders are conditions where the immune system is not functioning properly. This can result in an increased number of lymphocytes in the blood. Some examples of immunodeficiency disorders that can cause lymphocytosis include:.